I looked over my 270 Win data and I do have a good number of chronograph tests with IMR 4350 and AA4350 with 130 grain bullets. I don't remember why I picked 55 grains with a 130 grain bullet but I did. I am of the opinion that pushing a 130 grain bullet with any of the 4350's, at or close to 2950 fps is a maximum load. I cannot push a bullet as fast with IMR 4350 as I can with IMR 4831.
Notice the lot differences between a 1960's lot of IMR 4350 and a 1995 Accurate Arms Aa4350. Accurate Arms told me they blended their 4350 to the IMR pressure curve. Plus or minus.
FN Deluxe 24" Barrel installed new Wolff 22 pound mainspring
130 gr Federal Fusion (pulled) 55.0 grs IMR4350 wtd lot RBS (60's) mixed cases Fed 210S OAL 3.225"
8 Feb 2012 T = 50 °F
Ave Vel = 2942
Std Dev = 5
ES = 10
High = 2948
Low = 2938
Number rounds = 5
130 gr Federal Fusion (pulled) 55.0 grs IMR4350 wtd lot RBS (60's) mixed cases Fed 210S OAL 3.225"
14 Mar 2012 T = 80 °F
Ave Vel = 2952
Std Dev = 53
ES = 119
High = 2999
Low = 2880
N = 6
Here, AA4350 is OK at 50 F weather.
130 gr Nosler 55.0 grs AA 4350 wtd lot 9-1995 Rem cases WLR OAL 3.250"
8 Feb 2012 T = 50 °F
Ave Vel = 2961
Std Dev = 6
ES = 16
High = 2967
Low = 2951
N = 5
But when temperatures are 90's, that bullet is moving too fast for my comfort. I am sure pressures are over max due to shiny rub spots on the bases.
130 gr Fed Fusion Pulled 55.0 grs AA 4350 wtd lot 9-1995 FC cases, Fed210S OAL 3.250"
2 Sept 2014 T = 93 °F
Ave Vel = 3031
Std Dev = 15
ES = 40
High = 3053
Low = 3013
N = 5
probably over pressure: shiny rub marks on case heads, rounded primers.
A totally different barrel and yet I am getting 3100 fps in 55 degree weather. I don't remember shooting that load in 90 F weather in this rifle, but I am confident I would have been blowing primers.
M1917 Joe Pfeifer barrel Joe Donahue's rifle
Pfeifer Rifle Company Roscoe California
130 gr Nosler 55.0 grs AA 4350 wtd lot 9-1995 Rem cases WLR OAL 3.250"
19 Dec 2013 T ≈ 55 °F
Ave Vel = 3121
Std Dev = 30
ES = 104
High = 3192
Low = 3088
N = 15
This will not make we well loved by fans of the 270 Win, but you can't push bullets as fast in the 270 Win as you can in the 30-06. It is rather easy to push 130's to 3000 fps in a 30-06. I don't know if I have any 308 130's left anymore, and I don't know if they tumble somewhere between 300 and 600 yards. I remember reading pages on pages of material about how 130's in the 30-06 are inferior to 130's in the 270 Win because of the ballistic coefficient and lack of bullet drop, but this was all written by Lotus Eaters who never actually shot those bullets at distance to see how they expanded, or, if they tumbled. And the inch or two difference trajectory drop, at distance, is relatively insignificant when the shooter can't hit an eight foot by eight foot target at that distance. To hit at extreme ranges you really need to have an established zero, gained by shooting groups at that distance. And having sighters helps, as the wind always pushes bullets in unpredictable directions.
Gonna tell you, the difference between the men and the boys in long range competition is wind reading. Everyone has the same over priced equipment, everyone is shooting at the same time, all are hard holders. Its when you hear the groans coming down the line, that's when you know the wind has shifted and there are multiple train wrecks on the firing line. Even the best will get caught up in pick ups and let ups. After the relay, you will hear it later:
"did you catch the pick up?"
And I am such a poor wind reader, the only thing I can think of is
"what pickup?"
They used to run them hotter back in the day